1. Field of Invention
This invention relates to child-care, specifically to diaper usage and toilet training.
2. Description of Prior Art
Convenience of use, availability and easy disposal are the main factors that promoted the use of disposable diapers. While the advantages of these over cloth diapers are evident, the environmental impact of the growth in use of disposable diapers has been disastrous. Disposable diapers do not disappear when we throw them into a waste basket. The New York Times has named the disposable diapers as the premier "symbol of nation's garbage crisis". In the book Save our Planet Diane MacEachern says that we throw away enough diapers to fill a barge half a city block long every six hours of each day and we all pay an average $350 million annually to get rid of the so called disposable diapers, even if we have no kids. A child can use 8000 to 10000 diapers before becoming fully toilet trained and it takes twenty trees to keep one baby in disposable diapers for two years. About 800 million pounds of paper is used each year to make $3.3 billion worth of throwaway diapers, and no part of it is recyclable. This leads to the wastage of nearly 800,000 tons of plastic and 100,000 tons of paper pulp each year. With such compelling statistics one might think that even a small percentage reduction in use of disposable diapers would make a significant change in the total waste generated. This was one of the driving forces behind this invention.
Health of the baby was another major factor that led to this invention. Any parent who has seen a child suffer from diaper rash knows that it is a vary painful condition. Interestingly, it is also very easy to avoid it. The primary cause of this condition is long contact of the baby's skin with a wet diaper. The chemicals in urine penetrate tiny cracks in the skin surface and cause infection. Though there is medication available to treat this condition, minimization of length of exposure is the most effective way of prevention.
The only way to achieve above the goals of eliminating the use of diapers and keeping the baby dry, is to toilet train the child as early as possible. Toilet training is a difficult and tedious process for both the child and the parents. Making this process easier and faster was the third factor driving this invention.
The two usual methods followed by caregivers to perform diaper change are a) Timed Diaper Change and b) Change When Soiled. The former, as the name suggests, is performed at frequent intervals whether the diaper is soiled or not. The biggest drawback with this method is that since the diaper status is not monitored it could be soiled right after the change and will not be noticed till next change exposing the baby's skin to long hours of contact with urine. Since the diaper is changed whether dry or soiled, the diapers may not be used efficiently. Using each diaper to its limit reduces the number of diapers used, reduces cost of use of diapers and significantly cut down on waste generated.
The second method involves frequent checking of the diaper and changing when necessary. This method provides the most efficient use of diapers and ensures minimal contact of the baby's skin with a soiled diaper. However it is difficult to constantly monitor the diaper when taking care of several babies or when busy with other things. In practice, the caregiver normally performs a combination of the two methods.
Constant monitoring of wetness as a means of detecting soiled diapers can facilitate all of the above mentioned goals: reduction in skin exposure to chemicals, lower cost of use of diapers and lower waste generated. Automating this monitoring process would be ideal as it can save the effort of frequent checking. A product to detect wetness in a diaper has been attempted before. The most common approach has been through measurement of conductance between two locations on the diaper as shown in U.S. Pat. No. 4,205,672 to Karel Dvorak (Jun. 3, 1980), U.S. Pat. No. 4,704,108 to Shigeru Okada & Katsutoshi Rokuta (Nov. 3, 1987), U.S. Pat. No. 4,796,014 to Jack T Chia (Jan. 3, 1989), U.S. Pat. No. 5,264,830 to Michael J Kline, Paul A Pottgen & Nell J Szuminsky (Nov. 23, 1993) and U.S. Pat. No. 5,266,928 to Lonnie Johnson (Nov. 30, 1993).
In Dvorak the invention senses the wetness between a sensing conductor probe that is built into the diaper and the body of the infant. Dvorak requires one conductive pad inside the diaper material extending to the area between the baby's legs. This calls for a special diaper used for wetness sensing only with these detectors. Three drawbacks of this design are that special type of diaper with a conducting layer in the middle is needed for use with this device, one of the electrical terminals directly contact the infant's skin and the visual alarm is of little help when it is under clothing.
Okada et al., require two such conductive layers. The device by Okada et al. requires two conducting layers built into the diaper to operate. The invention senses the conductivity between them and generates an audible alarm. Again a diaper specially designed for this product is required.
Chia uses a safety pin with two conductors wound together as the sensing pick up and to hold the device in place. The safety pin has a unit with electronics to sense conductivity and generate alarm. Since the contacts are very close, chemicals could build up between them and change the isolation resistance between them, leading to faulty detection.
Kline et al., suggest a pair of outer waterproof pants with two terminals that contact the cotton reusable diaper when worn over it. The wetness monitor is snapped on to the terminals. The conductance between the terminals is monitored for wetness determination. The major drawback is that this could be only used with reusable cotton diapers that normally have no plastic outer layer and not with disposable diapers.
Johnson uses an elongated strip with two conductive pads for sensing conductance at an area on the diaper between the legs of the infant. This strip is connected to the monitoring electronics mounted on the diaper. This strip is discarded with each diaper while the electronic module is reused. Though this product can be used on any kind of diapers, a new conductance sensing strip need to be used with each new diaper to use this product. This could cause inconvenience of stocking these strips, the waste generated and higher cost of use of this product.